如果x2=4，y=1，那么x+y=______．
∵x2=4，
∴x=±2，
又因为y=1，
故x+y=3和-1．
故答案为：3和-1．
Tom is _____ honest man and now he is living in Belgium, _____ European country.
A．an, an
B．a, an
C．an, a
D．an, the
The price of the sports bag _____ ten dollars. [ ]
A. is
B. are
C. am
D. be
